GMSK – RAYmaps

January 13, 2020January 19, 2025BER Performance, Modulation

Orthogonal Minimum Shift Keying (OMSK)

In this post we consider a special case of MSK called Orthogonal MSK (OMSK) where the power of both the signals is the same (or almost the same) and there is no frequency offset. However, there is a phase offset of 90 degrees. As is evident from our previous posts MSK can be viewed as BPSK with information being transferred via in-phase (I) and quadrature (Q) carriers alternatively. In OMSK the interferer is 90 degrees offset from the signal of interest. So, when there is information being transmitted via I, interferer is on Q and when information is being transmitted via Q, interferer is on I.

December 18, 2019June 4, 2022BER Performance, Modulation

MSK – A Continuous Phase Modulation (CPM)

Some Background on MSK I – In the previous post we presented the mathematical model and code for BER calculation of a popular modulation scheme called MSK. However in the code we shared, we only considered one sample per symbol, which makes MSK look like BPSK. While BPSK symbols fall on the real axis, MSK symbols alternate between real and imaginary axes, progressing by π/2 phase during each symbol period. MSK signal thus has memory and this can help in demodulation using advanced techniques such as Viterbi Algorithm.

December 10, 2019June 4, 2022BER Performance, Modulation

Minimum Shift Keying Bit Error Rate in AWGN

Minimum Shift Keying (MSK) is a type of Continuous Phase Modulation (CPM) that has been used in many wireless communication systems. To be more precise it is Continuous Phase Frequency Shift Keying (CPFSK) with two frequencies f1 and f2.